Optical switching device

ABSTRACT

Respective end faces of two or more optical waveguides (23 to 29) are connected on one end face of a focussing rod lens (20) and a reflection means (21) having a reflection plane tilted with a specified angle (α) to the normal plane to the lens axis is disposed behind the other end face of the focussing rod lens (20) and angle of reflection plane of the reflection means (21) is varied by rotating the reflection means (21) around the lens axis (203) or by means of a piezo-electric driving device (30), thereby attaining selective switching of the waveguides (from 23 to selected one of 24 to 29) or varying the amount of rays to be transmitted through the waveguides (23 &amp; 24 of FIG. 4), or thereby modulating the rays. By utilizing a semitransparent filter forming another tilted reflection plane, the amount of attenuation for different wavelength or connection of the waveguides are controlled separately.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improvement in an optical devicewhich switches light transmission paths.

2. Prior Arts

One typical example of the conventional light path switching device isconstructed as shown in FIG. 1, wherein a first optical fiber 1 isconnected to a moving piece 2 of a magnetically responsive material suchas iron and second and third optical fibers 5 and 5' are fixed onrespective supporting members 4 and 4', which are secured on oppositeinner walls of a box 41. A pair of coils 3 and 3' are provided so as toinduce a magnetic force at excitation by currents therethrough to drivethe moving piece 2 either to the side of the supporting member 4 or tothat of the supporting member 4' responding to polarity of the currents.By driving the moving piece 2, the end face of the first optical fiber 1is put in front of the end face of the second optical fiber 5 or that ofthe third optical fiber 5', so that light is transmitted from theoptical fiber 1 to the optical fiber 5 or to the optical fiber 5'.

The abovementioned conventional light path switch has such shortcomingsthat the end part of the first optical fiber 1 is liable to damage in arelatively short time due to repeated shocks when driven between thesupporting members 4 and 4', that a considerable gap is necessarybetween the end faces of the first and the second optical fibers 1 and 5or between those of the first and the third optical fibers 1 and 5', andthat it is difficult to construct a light path switch capable ofselectively switching among three or more light paths.

Though there is known a light path switching device utilizing a lenssystem, it is too large and has an excessive loss of light for practicaluse.

SUMMARY OF THE INVENTION

The present invention provides a simple structured light path switchingdevice with low loss and capable of switching among three or more lightpaths.

The present invention is an optical device comprising a focussing lens,at least two optical waveguides having their end faces on a focal planeof said focussing lens, a reflection means disposed in an opposite sideto said focal plane with respect to said lens, and a means forcontrollably moving said reflection means such that rays issuing fromone of said end faces of the optical waveguide and passing through saidlens is reflected to pass through said lens in variable substantiallyinverse directions, including at least a direction for entering intoanother one of said end faces.

BRIEF EXPLANATION OF DRAWINGS

FIG. 1 is a perspective view showing an example of the conventionallight path switch.

FIG. 2 is a schematic view showing principle of the device in accordancewith the present invention.

FIG. 3(a) is a front view of an example of device embodying the presentinvention.

FIG. 3(b) is a sectional side view at the sectional plane I--I of FIG.3(a).

FIG. 4 is a side view of another example in accordance with the presentinvention.

FIG. 5 is a perspective view of another example in accordance with thepresent invention.

FIG. 6 is a side view of another example in accordance with the presentinvention.

FIG. 7(a) is a front view of an example in accordance with the presentinvention.

FIG. 7(b) is a sectional side view at the sectional plane I--I of FIG.7(a).

FIG. 8 is a sectional side view of another example in accordance withthe present invention.

FIG. 9 is a block diagram of the electric circuit of the device of FIG.7 or FIG. 8.

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention provides an optical device, wherein, as oneexample, switching of optical waveguide can be made without moving theoptical fiber.

The principle of operation of the present invention is elucidated withreference to FIG. 2.

On a focal plane 9 of an optical convergence lens 6, a light sourcepoint 10 is provided. A reflection means 11 (a plane mirror) is disposedin an opposite side to said focal plane with respect to said lens 6. Thenormal line of the reflection plane of the reflection means 11 isselected to have a small angle α° to the axis 7 of the lens 6. If rays12' are emanated from the focal point 8 on the focal plane 9, the rays12' are converged by the lens 6 to form parallel rays 12. In suchoptical system, when the line connecting the point 10 and the opticalcenter of lens 61 has an angle θ to the lens axis 7, rays emanated fromthe light source 10 and converged by the lens 6 becomes an inclinedparallel rays 13 having the angle θ to the lens axis 7.

Provided that:

d . . . distance between the focal point 8 and the light source point10.

f . . . focal length of the lens 6 (i.e., the distance between thepoints 61 and 8),

tan θ=(d/f) holds.

Then, when a relation 2α=θ holds, then rays, which are emanated from thelight source 10 are converged into the parallel rays 13 by means of thelens 6, are reflected by the reflection means 11, thereby formingparallel rays 13' which are parallel to the lens axis 7, and whichconverge on the focal point 8. By means of known principle of geometricoptics, when the light source is disposed at the focal point 8, then thereflected rays converges on the point 10. The distance between the focalpoint 8 and the point 10 responds to the angle α. As a conclusion, raysoriginated from the focal point 8 and reflected by the tilted reflectionmeans 11 converges on a point on the focal plane 9. This law is utilizedin the device of the present invention.

Hereinafter, the present invention is elucidated referring to FIGS. 3(a)to 9 showing several preferred exemplary embodiments.

In FIG. 3(a) and FIG. 3(b) which show a first example, on one end face201 of a known light focussing rod lens 20 of about 1/4 pitch length,are contactingly disposed end faces of seven optical waveguides 23, 24,25, 26, 27, 28 and 29. The end face of the waveguide 23 in the centerposition is disposed on the axis of the lens, and the end faces of theother six waveguides are disposed on the equal distance from the lensaxis 203. On the other side of the rod lens 20 are disposed a tiltedreflection means 21. The normal line of the reflection plane 22 of thereflection means 21 has an angle α° to the lens axis 203. Accordingly,the reflection plane 22 is tilted by α° to the plane 202 which is normalto the lens axis 203. When the angle α is selected to be a specifiedvalue, rays coming from the central waveguide 23 into the rod lens 20,reflected by the tilted reflection plane 22 and traveling through therod lens 20 focuses and enters into the waveguide 24. When thereflection means 21 is turned clockwise by 60° around the lens axis 203,the reflected rays focusses on the end face of the waveguide 29. Byfurther turning the tilted reflection means, the reflected rays can beled to either of six waveguides 24, 25, 26, 27, 28 and 29.

When optical waveguides with core-diameter, clad-diameter and numericalaperture of 100 μm, 150 μm and 0.28, respectively, are used for theseven waveguides, together with a focussing rod lens 20 having 2 mmdiameter and 20.8 mm pitch length, the angle α becomes α≈2.1°. This isempirically confirmed. Average insertion loss of this example was about1.0 dB. When a stop motor was used to drive the reflection means, theswitching time was about 15 m sec. FIG. 4 shows another example, whereinthe tilted reflection means 21 can be quickly driven by means of apiezo-electric driving means 30, so that switching of the opticalwaveguide can be made very quickly. The piezo-electric driving means 30has a sandwich type bimorph structure having two layers ofpiezo-electric substance and electrodes. For each of the piezo-electricsubstance, 20 mm long and 0.2 mm thick PZT (lead titanium ziroconiumoxide ceramic) can be used. A small reflection mirror 21 is bonded onthe sandwich structured driving means 30, and a pair of stoppers 30' and30' are disposed so as to define the right angles of the reflectionmirrors 21. Other parts are constructed similarly to those of precedingexample. By employing optical waveguides of 120 μm outer diameter andfocussing rod lens of 2 mm diameter and 32 mm pitch length, the angle αbetween the plane normal to the lens axis and the reflection plane ofthe reflection means 21 is about 1.0°.

By switching the impressed voltage across the electrodes of thepiezo-electric driving means from -134 V to +134 V, by applying a stepvoltage, the driving means is driven by known piezo-electric effect, andchanges the angle of the reflection means 21 and switches the opticalwaveguide. The time period for the switching of the optical waveguide isas short as only 15 m sec.

As an alternative configuration, the driving means 30 can be constitutedby utilizing an electromagnet.

By selecting the angle of the reflection means intentionally to be outof the abovementioned theoretical angle, the incident light to theoptical waveguide does not fully enter into the waveguide 24, and ispartly lost. Accordingly, the device of FIG. 4 works also as a variableattenuator, or an optical modulator.

FIG. 5 shows another example comprising a semitransparent reflectionmeans, for example, a filter 31, which for example reflects light of awavelength λ₁ but passes light of another wavelength λ₂. The filter 31is disposed in front of the reflection means 21. The filter 31 and thereflection means 21 are tilted by the same angle α to a normal plane tothe lens axis. And both the filter 31 and the reflection means 21 aresupported so as to be separately rotatable around the lens axis by knownmeans. Other parts are constituted in the same way as the precedingexample of FIG. 3(a) and FIG. 3(b).

Provided that two light signals λ₁, and λ₂ enter from the centralwaveguide 23 into the rod lens 20, the incident rays become parallelrays when get out of the other end of the rod lens 20. Then the rays ofthe wavelength λ₁ are reflected by the filter 31, while those of thewavelength λ₂ are reflected by the reflection means 21. Therefore, whenthe faces of the filter 31 and the reflection means 21 are in theposition as shown in FIG. 5, the rays of the wavelength λ₁ are focussedon the end face of the waveguide 24 and those of λ₂ on that of 25.Accordingly, by turning the filter 31 and the reflection means 21separately to a desired position, the rays of λ₁ and of λ₂ can beseparately led into desired one of the waveguides 24 to 29. As amodification, by using a neutral reflection mirror in place of thefilter 31 and by forming the reflection means 21 by a dichroic mirror,dividing the light in formation is also possible.

FIG. 6 shows a further modified example comprising two set of opticalswitches and is capable of switching the waveguide connection of theseswitches in an interlocked relation to each other. In FIG. 6, a pair ofrod lenses 20 and 20' are disposed with their lens axis in parallelismto each other. On the faces of one end of both of the rod lenses 20 and20' are connected bunches 100 and 100' of seven optical waveguides. Forboth rod lenses, a common reflection means 21 (a tilted plane mirror) isdisposed with a rotatable supporting means 32'. The axis of the rotationof the reflection means 21 is disposed in parallelism with the axes ofthe rod lenses 20 and 20'. Other details are constituted in the samemanner as those of the example of FIG. 3(a) and FIG. 3(b).

In the device, by turning the reflection means around the shaft of itssupporting means 32', the light from the central waveguides of bunches100 and 100' are reflected by the reflection means 22 and are input tothe respective upper waveguides of the bunches 100 and 100'. Therefore,by turning the single reflection means 21, both switches for the bunch100 and for the bunch 100' can be driven simultaneously in theinterlocking relation.

FIG. 7 shows another example, wherein a means for transmitting acontrolling signal is provided in the system. In the device of FIG. 7,the end faces of the central waveguide 23 and that of the lowerwaveguide 25 are disposed symmetrically with respect to the lens axis33. The axis of rotation 32 of the supporting means of the reflectionmeans is selected to be parallel to the direction of the output rayswhich are issued from the central waveguide 23 to the rod lens 20 andput out of the rear end face of the rod lens 20. The reflection plane ofthe reflection means 21 is tilted by the angle α to the plane normal tothe axis of rotation 32. By so constructing, when the reflection meansis in the position shown in FIG. 7, the rays issued from the centralwaveguide 23 are, after reflection by the reflection means 21, put intothe upper waveguide 24, while the rays originated from the centralwaveguide 23 and reflected by the rear end face 34 of the rod lens areput into the lower waveguide 25. When the reflection means 21 is rotatedaround its axis of rotation 32, the waveguide to which rays originatedfrom the central waveguide 23 are put shifts from 24 to 26, 27, 28 and29. Of course, the rays from the waveguide 23 are put into the waveguide25, but this connection is not utilized since the waveguide 25 isalready used to transmit the abovementioned partially reflected rays ofthe central waveguide 23. Irrespective of the position in the rotationof the reflection means, the waveguide 25 receives the abovementionedpartially reflected rays of the central waveguide 23. Therefore, bysuperposing a control light signal for rotating the reflection means 21on the information light signal to be put in the central waveguide 23,and by picking up the control light signal from the output of thewaveguide 25, it is possible to switch the optical device totally bymeans of the light signals.

FIG. 9 shows a switching system utilizing the optical switch 44 inaccordance with the examples of FIG. 7. In FIG. 9, a central machine 40puts information signals I and control signals C into the centralwaveguide 23 and a partial output divided by the partial reflection isgiven to a control circuit 49 through the waveguide 25. The controlcircuit controls the position of the reflection means responding to thecontrol signal given from the central machine 40. By means of theelectrical output of the control circuit and by the rotating motion ofthe known driving means, the reflection means is rotated and therebyswitches the optical waveguide to connect the waveguide 23 to a selectedone waveguide 24, 26 or 27. By such connection, the terminal machine 41,42 or 43 and the central machine 40 are connected by the opticalwaveguides with each other. Accordingly, light signal can be transmittedin either of desired directions, from the central machine to one of theterminal machine or vice versa.

As a modified example, the control light signal can be picked up from asurface of semitransparent reflection means such as a filter which isdisposed in a normal plane to the lens axis immediately behind the rodlens 20 and capable of transmitting a specified wavelength andreflecting another specified wavelength used for the controlling signal.

FIG. 8 shows another example of an optical switch provided with a meansfor transmitting a controlling signal. On the front end face of a mainfocussing rod lens 20 are connected end faces of a specified number ofoptical waveguides (omitted from the drawing) similarly to the examplesof FIGS. 3(a) and 3(b) and FIG. 5. Behind the rear face 205 of the mainrod lens 20 is provided a tilted half mirror 21, which is tilted to havea specified angle to a plane normal to the lens axis, which partlypasses and partly reflects the rays incident thereon. Further behind thehalf mirror 21, follows an additional focussing rod lens 22 and aphotoelectric transducer 35. The rays which passed the half mirror 21are focussed on the photoelectric transducer 35 by the additional rodlens 20', thereby to produce the control signal for rotating the halfmirror 21. The half mirror 21 can be a filter which selectively passesrays of wavelength used as the control signal.

In any of the preceding examples, it is possible to give the transmittedsignal a desired degree of attenuation by finely and continuouslychanging the tilt angle of the reflection means (or mirror) to make thereflected rays focus only partly on the end face of the designatedwaveguide.

As described above, the optical device in accordance with the presentinvention has the following advantages: The optical waveguide ispermanently connected to the end face of the lens in a satisfactorycondition and is not moved for switching, and accordingly the delicateend part of the optical waveguide is free from damage by switchingoperation and moreover the system has good transmission characteristics.When piezo-electric driving means are used to drive the reflectionmeans, a very high speed switching, and a high speed change ofattenuation, can be achieved hence modulation can be made. By adjustingthe tilt angle of the reflection means, desired degree of attenuationcan be given to the transmission signal. By employing a filter as thereflection means, selective switching for different wavelength signalscan be made. By selecting the arragement of the end faces of the opticalwaveguides on the end face of the rod lens, taking of the control signalout of the information signal in the live transmission waveguide can bemade without inserting an undersirable dividing network in the opticalwaveguide circuit, and without degeneration of the transmissioncharacteristics.

What we claim is:
 1. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, and an additional reflection means provided between said focussing lens and said reflection means, said additional reflection means being semi-transparent to reflect certain wavelength rays and transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 2. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, and an additional reflection means provided on the side of said reflection means opposite said focussing lens, said reflection means being semi-transparent to reflect certain wavelength rays and transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 3. An optical switching device comprising:a first focussing lens, a second focussing lens, respective central axes of said first and second focussing lens being parallel to one another, a first waveguide set having a plurality of optical waveguides having respective end faces disposed on a focal plane of said first focussing lens, a second waveguide set having a plurality of optical waveguides having respective end faces disposed on a focal plane of said second focussing lens, reflection means disposed at the ends of said first and said second focussing lens furthest from the respective focal planes thereof for reflecting rays incident thereupon issuing from said first focussing lens and said second focussing lens, and means for controllably moving said reflection means, rays issuing from one of the end faces of said first waveguide set and transmitted through said first focussing lens, and rays issuing from one of the end faces of said second waveguide set and transmitted through said second focussing lens, being controllably reflected by said reflection means in respective selected direction, including respective specific directions to enter selectively into at least one respective end face of said first waveguide set other than the end face thereof from which rays issued, and into at least one reflective end face of said second waveguide set other than the end face thereof from which rays issued.
 4. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, a control signal optical waveguide disposed for receiving rays reflected by a semi-transparent reflection means having a reflection plane normal to a central axis of said focussing lens, and control means responsive to an output of said control signal optical waveguide for controlling said means for controllably moving said reflection means.
 5. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furthest from the focal plane thereof, said reflection means being semi-transparent for reflecting certain wavelength rays and for transmitting certain other wavelength rays, means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, means for collecting the rays transmitted through said reflection means, said collecting means being disposed behind said reflection means, and control means, connected to said collecting means and responsive to an output thereof, for controlling said means for controllably moving said reflection means.
 6. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furtherest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, the movement being a rotation about a central axis thereof, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided between said focussing lens and said reflection means, said additional reflection means being semi-transparent to reflect certain wavelength rays and transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 7. An optical device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means having a planar reflective surface tilted relative to a central axis of said focussing lens and being disposed at an end of said focussing lens furthest from the focal plane thereof, for reflecting rays incident thereupon, and means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided between said focussing lens and said reflection means, said additional reflection means being semi-transparent to reflect certain wavelength rays and transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 8. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, the movement being a recurrent change in an angle of said reflection means relative to a central axis of said focussing lens, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected direction, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided between said focussing lens and said reflection means, said additional reflection means being semi-transparent to reflect certain wavelength rays and transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 9. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, one of said end faces being centrally disposed relative to the end faces other than said centrally disposed end face, the end faces other than said centrally disposed end face being arranged around said centrally disposed end face with uniform distances therebetween; reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided between said focussing lens and said reflection means, said additional reflection means being semi-transparent to reflect certain wavelength rays and transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 10. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furtherest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, the movement being a rotation about a central axis thereof, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, and further comprising: another focussing lens, and another plurality of optical waveguides having respective end faces disposed on a focal plane of said another focussing lens, said focussing lens and said another focussing lens having respective central axes parallel to one another, and said reflection means being disposed at an end of said another focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon issuing from both said focussing lens and said another focussing lens.
 11. An optical device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means having a planar reflective surface tilted relative to a central axis of said focussing lens and being disposed at an end of said focussing lens furthest from the focal plane thereof, for reflecting rays incident thereupon, and means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, and further comprising: another focussing lens, and another plurality of optical waveguides having respective end faces disposed on a focal plane of said another focussing lens, said focussing lens and said another focussing lens having respective central axes parallel to one another, and said reflection means being disposed at an end of said another focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon issuing from both said focussing lens and said another focussing lens.
 12. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, the movement being a recurrent change in an angle of said reflection means relative to a central axis of said focussing lens, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected direction, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, and further comprising: another focussing lens, and another plurality of optical waveguides having respective end faces disposed on a focal plane of said another focussing lens, said focussing lens and said another focussing lens having respective central axes parallel to one another, and said reflection means being disposed at an end of said another focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon issuing from both said focussing lens and said another focussing lens.
 13. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, one of said end faces being centrally disposed relative to the end faces other than said centrally disposed end face, the end faces other than said centrally disposed end face being arranged around said centrally disposed end face with uniform distances therebetween; reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, and further comprising: another focussing lens, and another plurality of optical waveguides having respective end faces disposed on a focal plane of said another focussing lens, said focussing lens and said another focussing lens having respective central axes parallel to one another, and said reflection means being disposed at an end of said another focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon issuing from both said focussing lens and said another focussing lens.
 14. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furtherest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, the movement being a rotation about a central axis thereof, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided on the side of said reflection means opposite said focussing lens, said reflection means being semi-transparent to reflect certain wavelength rays and to transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 15. An optical device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means having a planar reflective surface tilted relative to a central axis of said focussing lens and being disposed at an end of said focussing lens furthest from the focal plane thereof, for reflecting rays incident thereupon, and means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least one specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided on the side of said reflection means opposite said focussing lens, said reflection means being semi-transparent to reflect certain wavelength rays and to transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 16. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, the movement being a recurrent change in an angle of said reflection means relative to a central axis of said focussing lens, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected direction, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided on the side of said reflection means opposite said focussing lens, said reflection means being semi-transparent to reflect certain wavelength rays and to transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions.
 17. An optical switching device comprising:a focussing lens, a plurality of optical waveguides having respective end faces disposed on a focal plane of said focussing lens, one of said end faces being centrally disposed relative to the end faces other than said centrally disposed end face, the end faces other than said centrally disposed end face being arranged around said centrally disposed end face with uniform distances therebetween; reflection means disposed at an end of said focussing lens furthest from the focal plane thereof for reflecting rays incident thereupon, and means for controllably moving said reflection means, rays issuing from one of said end faces and transmitted through said focussing lens being controllably reflected by said reflection means in selected directions, including at least a specified direction to enter selectively into at least one respective end face other than the end face from which said rays issued, wherein an additional reflection means is provided on the side of said reflection means opposite said focussing lens, said reflection means being semi-transparent to reflect certain wavelength rays and to transmit certain other wavelength rays, for cooperating with said reflection means to reflect different wavelength rays in respective different directions. 